1. Field of the Invention
The present invention relates to an article having a color pattern (colored layer) formed on a substrate, such as a color filter or an electroluminescence element for use in a color display device or the like.
2. Description of the Related Art
A color filter for use in a color liquid-crystal display device is an indispensable component of such device and serves to improve image quality of the liquid-crystal display device and provide the primary colors to each colored layer (pixel). Methods for manufacturing color filters have been actively studied, and examples of known representative methods include a photolithography method and an ink-jet method. With a photolithography method, coating films of photosensitive resin layers of each color are formed on the entire substrate and then unnecessary portions of the coating films are removed and the remaining patterns are used as colored layers of each color. For the most part the coating films become unnecessary in this method and, therefore, a large amount of materials such as pigments are wasted when a color filter is manufactured. In addition, the number of production steps is large because exposure and development are carried out for colored layers of all colors. Accordingly, in the manufacture of color filters by photolithography, problems are associated with both the cost and the environmental aspects. In particular, the size of liquid crystal displays has been increasing in recent years, resulting in corresponding increase in the size of color filters and the amount of wasted materials. An ink-jet method has recently attracted attention as a method for manufacturing color filters that resolves the aforementioned problems. When a color filter is manufactured by an ink-jet method in which inks are locally sprayed from ink nozzles, the inks of each color of the colored layers of three colors R, G, B are printed simultaneously. Therefore, the process is implemented in one cycle. As a result, waste of colored resin compositions such as pigments practically does not occur and at the same time the process of forming colored layers of three colors can be shortened, thereby making it possible to expect the reduction of environmental load and a significant cost reduction.
Methods described in Patent Documents 1-4 are suggested as methods for manufacturing a color filter by using an ink-jet process. Patent Document 1 describes that in order to prevent the spread of ink to the outside of the desired coloration region on a glass substrate, a color pattern is formed by introducing a water- and oil-repelling agent based on hydrofluoric acid in advance into banks, thereby fixing the ink only within the coloration region. Further, Patent Document 2 and Patent Document 3 describe that a monochromatic resin layer comprising a fluorine-containing compound and/or a silicon-containing compound is used as a bank for preventing ink bleeding and color mixing in the coloration process. In Patent Document 4, an ink head is prevented from clogging by using a solvent with a high boiling point for the ink.
However, with the above-described conventional methods, colored layers are formed by ink jets, then the solvent component of colored resin composition of each colored layer is dried within a short time at a low temperature, and then the thermosetting resin components of the colored resin compositions are cured. The resultant problem is that the post-bake process of the thermosetting resins involves two heating stages and becomes long. Another problem is that the colored resin composition cured in each colored layer (referred to hereinbelow as “cured colored resin”) is not sufficiently flat and has a convex shape. For this reason, a spread occurs in the shapes of colored layers of color filters, causing problems such as nonuniform color in color liquid crystal display devices manufactured using the color filter.
The present invention was created to resolve the above-described problems and it is an object of the invention to provide an article having a color pattern formed therein, wherein each colored layer has a flat color pattern. Another object of the invention is to provide an article having a color pattern formed therein in which a spread of color of the colored layers is suppressed, this article having excellent required characteristics such as low cost and short production process.    Patent Document 1: JP-A-6-347637    Patent Document 2: JP-A-7-35915    Patent Document 3: JP-A-7-35917    Patent Document 4: JP-A-2000-310706